Basic Kinematics question

A car traveled up a hill at constant speed of 10.0 m/s and then returned down the hill at 20.0 m/s . If the time to turn around is ignored, what was the average speed for the trip?

Now i like to struggle to figure out questions myself but i cant seem to figure this one out. I have most of the kinematics formulas in front of me too. If anyone could help to give me a hint or a clue it would be great. thanks an advance.